SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b64bee5d0eaea6d9c52c600f78d8e06a4297c40c7bbc6f943734424039b84b3' 
  AND token = 'JUr3Gn1Un3vQ1NQdv6ToR/7ZzITggRwp2JjPzZeV04c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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