SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29b13cf78dbefed156035516bbc654003888ab194deff54ecadf21756c854d64' 
  AND token = 'L83v5FlCTKROA/Ez9ci9SEpXP8BJUZfsSxnbxAvnCV0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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