SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14fb7ff6874f50934c4107f2632760af541cc113b19081df3e54bf2441c7f4f4' 
  AND token = 'DruNRITjymKkqu6hTdsVLnyd2dqhGrBoR8cNyBGJd8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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