SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '710a7ed29eddc024d7b4c09739f4dd1333669e777c26d89c022b449408df2fc1' 
  AND token = 'FgMobmmIVZAVo3Shj0SUU6EMCx07Qju6fHsK3RWJNK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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