SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '03a29d28eff61ff8c1da45243601bd6e8d836fb269ecd58cdd9ab7b9707d09f3' 
  AND token = 'XQwBmFXMIPrc1CuUFTmCR9UOqFoQ8JEzqIc3jgp7NDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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