SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7c0c6b388ae302936feafb05283c3998bfa75c4eb172c3fc2da7b2fc6361e011' 
  AND token = 'SEQ8HWSOrr2WyB1Zx4r0YIOgIodBp5Ojzb3Q0L+wlRg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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