SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0274c0293b29758d019491ca2cc6916d079788ff7c1b9eafb6406b00ce4e792b' 
  AND token = 'KbdxFIxfSTkrDk3t4f9jJNuRNgMsRHOYTiahGLIEla0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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