SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c7b9c1961a90aa6a0aaffd93d7388187c36252fa2e62b59825ed3d906a9125b' 
  AND token = 'c+VhG6LYjJS7/yWvKMpXxUUOGUB92VMK6EhOw+IaG5I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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