SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff8dcfdf3c4197b962b8cefe9dbf11152272a61db5936946824288c2ef8ba3e0' 
  AND token = 'mzlnd/AsNR8xhAHiQc5oukVQno3N2dfglgNDcUqVY/g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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