SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7598a815e60203cb1f432c6066c3ecffd944a12760b5716abf9ded0a9768aff7' 
  AND token = 'wY24VXgTrJryhFPJfrKUXCtBebxBhcDejIqdzCoZLhs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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