SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27bcda412ab9be737cbaf5e1f341dc91c4e408a372d2fc9c75bf46a63c1934f3' 
  AND token = 'LDEIPPyASa4r6DSGbN0ertdyK+yXwIYUWboFOpfyo1E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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