SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf46e406c5f672536e5be61c3f5b4afa3dc8e3d749305a810f9cac69ff60da1f' 
  AND token = 'JeiEBY/foP3zKATrCrRzLoVHp3fy2dz67yYIZELrAGc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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