SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fa62726c98956d3b6c54480d3920c98c5f58186bcbdcf73b24063f11e407f90' 
  AND token = 'IFpcFPQtcfVHGMw8UmECwvOrOjkIL4z2GIdFdzYv+00=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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