SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6c472f1d433b7042ac6b0d7bc909aa88d27071b938d14a6c4556a0ba0a96dab5' 
  AND token = '6TJOi3mlHv/L6y5ZJwJGpVUMzDvZq9+/uHOrwq2k0yU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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