SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd84685084527b187557e0dc9cb5d89c697a0620b061f423a9080e4f68d3775c' 
  AND token = 'FI/q5RFnh6YrIblk+MsuPYvuTqYZxRdUxGPV5p6z6BM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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