SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d389faca65a0599fc9f502508228febf34512781dcbdb55d8527696b0c2fd09' 
  AND token = 'WfLo+jMOSxFEe/n6t2pln5KJgwUvaCy4EzwvUXbMz1o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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