SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '250fcaaa20aa154ce4240959f06b6e768ca889462cf70cd2f59dfd353cfff0e2' 
  AND token = 'UbUXYGKPCYbfGsxJ7vDKfEDyw0elWronGhYIDrYI14s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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