SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ac9e4c13802130f316acd056b670d8561d9cfbd2456fafb400536e608bef06a' 
  AND token = 'ZP9CDkhpDhTnm6aYd6ZYufZEwoP16txOzFHHITu4pas=' 
  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"
    }
  }
}