SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ca2e132feb86e471751c3fa0b491fbc9882e389db0571cda07fc5fda260c0ad' 
  AND token = 'NcCybYEjwSA+iklstaQQjyzgBjemSJsXGttvFHi2bpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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