SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '2436be3bd3f37ebc3561fcf4b742b0eeb32563f12e999d4da5756275c96f52f0' 
  AND token = 'l/JyvIuLGVadO0HBtOagzWWbUSOOtlqJbtZAvqe+N0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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