SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd28defc22dead7070f486db9dab3023e5eee842ad61401ee61d3d0173871f466' 
  AND token = '7NifDjEO4V5RFmvxiLJJQyiB6xp1PscaJIr0mIa94Mc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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