SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0b29f2c55d67602785750d90774fd5a36c58de16d8958c528e035eb2bd3f52c' 
  AND token = 'xusgW5ZSvC7xg32dThva9IvfZZoIC5Br2lZOlOmdkuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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