SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6cd47c8f56bc6698787fc150f09f557a117f2651d1330101589f4dc3b483f532' 
  AND token = 'kYKJlykp0A4YJacyhQ9Xi7lm7heIDpD8p/z9r1nbiJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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