SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '629cc44ceabc874d4a319f9095b9fe3397a15072e92844140a6b8ce9a9ab337c' 
  AND token = 'rin9KMhbtV2BRgaGMcZODJXaCZ3PBJMJM0a4Obs+vGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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