SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1dd286bd5ade7e81384fe4635bbdc3dd2e47699c91821cce1a933501d2c3520' 
  AND token = 'NLqzj3mtz9ghSb1B2SSxKTzLFHbMGYecAtoUXQzFiBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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