SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '74a3bb2cf3e57358eb9e1c0dfeb251dc6a035f41f494745a4efc847a5b1d1146' 
  AND token = 'pFJWZ+StWbikuHr3oyKVH0CgfoXKoE4cmppxu/NF3yM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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