SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1323e614338001886fc758df404f4e8f8f17b59dc997bde3b435bc3a6f5e31d3' 
  AND token = 'dFfBY6EqDDF1jbqhCPXb8fuKZ9jTi6ewhaJeSgtmOaw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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