SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9dea2fb53cb43b2cbdce8ff790d1631ebb93fdbd0832c8eb72a65b024615383f' 
  AND token = '9/SplV1Ho8ID1u8+K/IJ/Fks9L3ejjz5r7eHCJtrlI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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