SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f548a8926904d330410c816ca71530799914d24b7651ac67f146bd8dbd9ccd78' 
  AND token = 'X2Vyq7QrgStZFMnzu0P2PgWd2w894wLlM2FZ3funtBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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