SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '03a08e8b2d319cbb96dc928dbdee650ae51c5353f3e04b205c3f3387c5adde2b' 
  AND token = 'teEYxUszdnnKWPkpSUfhbatFzxF10v3nkmB8HGjObfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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