SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1491d4828b3e3432b02dc227612165174d7aa7bf4dc6e0a4a98f04368fce9096' 
  AND token = 'g0bzrmpGqdph7xI4O8lTjndtqVxqBftDsHjZckC+YII=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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