SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '286e1cb1d04c17922d5229051c9d989bfe17721c9c3c1c28e63cd40d1fabe06a' 
  AND token = 'uAKo52VZhG8oJodwbvzp2kZqpab+WtF7kAM2dmtBFLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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