SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0a7da0c072a5125e80d13d4085e50adad6f424c7dbe573600e84282aa4f21a83' 
  AND token = 'pH9wroQS3CZjDIQS7QZqBmxJfMqLctBUUp/trM24LrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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