SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c2678f85a69997778e3c4471bd3b188ec7af51a0440a3e8fb826ee6f04ef5bc' 
  AND token = 'rIlk42uJqUgDF1dLOzgNvMlLMVcq3do0t6viVYR6nj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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