SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd15590ed9abdd793cb96f6745434f21f5472f8d6a0448aed37f37f33b4493df0' 
  AND token = '2aySupCwdmPqmNDmK+kxwBm1+49SbZlCUGlgWtDbjuk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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