SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7bdc314e0d639e724ab41010ccb4bbc270d858dd546dee2ffc11dba2df987b83' 
  AND token = 'JwXoH0ZhzcxhPX2KXnqDIG5VryCCxDFFmgCX24LidYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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