SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '286c17141f375b8cb820ad1ee348ed399d84466f9012e3176d33288831d7ae28' 
  AND token = 'hR4XijDTeFR0WMLNRhS+NHF++kFiFih4XigMWBGs2W4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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