SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca7b938f8483a7bb872cc487ed4faad8f90f76cc8e5af4ab752a2da46393e3d6' 
  AND token = 'EH8VGunud3RBjpFaW8e+Fs5pzZIKD1g9rV77JXPO/3M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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