SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '031acc9261c2ce0ff5cd474685a808fc88fc9caa0b7853c5493859de2c876877' 
  AND token = '/LnIsDLY63KOJrGvIhuJJdzP+GzQQmrtMxF1EFLZ448=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}