SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ed7b475f15286e45386c334098108fc715f7001428ad9d16a74603be5178bc85' 
  AND token = 'zSw3jOnCA0nykxB/BTZHgPm5aJwNkzL9aj9TxdvQDp8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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