SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6601b5f69fff979de24a24c28aff29cbf5516dd0c1debd8a41bb7513adcbda7e' 
  AND token = '0jBwSYwKdh81/M/oEsbt6a67wpShB9Q1SCeSUInPQC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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