SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2c7d443fef1f00950978f8c735d0695915ab43612ba9b3cfc6fb858264c1707' 
  AND token = 'D9AglGUYCOSHeDd638Yc+o3tF2IVPvjRjVKh+NvEjM4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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