SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2c64d64975e70bdce12d17a548eb9a5b15321b207d56fc39a3a6efbc4b45f7b' 
  AND token = 'E+T1ao2HZlJeqIiownmNnp4cL+XqWCmqa8xCBW5Evpk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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