SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35d8698b090f2a737c64316fc83284a5392d44b540a0807463197e2b18f0757c' 
  AND token = 'Ug4Y9tJQgFFgM2Oy8sOjjtmmUJCGMRH7Cq/zgc6DpI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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