SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fa7789fa0716daf0c33d57bdcf4041d67edbf899d0a0af21db97bc6bdd553ab' 
  AND token = 'bt7POc0QKmohlHkJ5Pc8rt7VgjXoeiVoRFYp8ZytZHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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