SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6542986d081ed71f473b7e0bc23097b554cb6cdfb517f68534d0e6cabbc5e2b8' 
  AND token = 'yr3I4m+uhzWbrxi0oVLTOiYf/UnV6NdniA7pK4Btfh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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