SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fd8baa273085f9dabc6034b0cb318891e3b9fc9c6d62b21986758b3ac72415e' 
  AND token = 'd4gZxmYXk8UW2SNuPKP9pvLCKbccpjVFKLLssmYq2o0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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