SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2a39251c860f40cea629977801d92ec13e8d8f4d46740134a359030b1667bf91' 
  AND token = 'Cfz9BJLpbvNKuTdvF9E+f9L2++dyPMPhqr/C1ezmrxA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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