SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '848210149dcf8c7316be43482702d1773a67784b518d87c15bbcee97b28ca324' 
  AND token = 'hk3tTnX1bDgiMeYhBr42qLJE9vA6rfy7rI/hUohRcu8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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