SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfb80ca7979fc3debfd462265b74d71812a774ddeafc22a694661866d96aecb8' 
  AND token = 'JzsP3m8hJm096RQmdSsRIgUru9Gy/2zAraRkMV69vIc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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