SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd27410f8fadbf41d4df7e67958530d3eaf4eddcbbd88bd2d47962c0fdf332c6' 
  AND token = '+PBIQsqdFVKeSin1fh2tjF4v5I/hhdSMIsGfIz0D4YI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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