SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fe8dab021c4409b22531c989fcb6808e5fb4326db0fd8ae0d38f864f40ede442' 
  AND token = 'iE6FkhnmqwqJqrW86b60g14I1AeYebayBvwudTBkzkg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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