SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e256597856bd75554ba0c5714a83365ed69c3cc739371b8d982488b1c3a163c0' 
  AND token = 'fgCj7OBzqwqXXoDLDG0BRx+KIi+FcjM6vdxBHJo0uLk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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