SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9e6c617f8ba3cb8ad628ac067a1203f5143fb90bd26a3662e9ab121f5f43467' 
  AND token = 'UcYNbGFuXL0UQV/ga0UixWI/IMthUGqftOwk7XfBNI8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}