SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e96182ca723c3d6bfb0b656bbb9b5c85f949ff4120cdba0b35f8b227cb37a14' 
  AND token = 'MdvUnbbVifRvsdXJ8dFG6/aBeDyboDXHN2KIgufS8ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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