SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78bef5b6da2619780b4420a1f08aaac227eb867692c8c8a3119e3996ca2de88e' 
  AND token = 'Df7HnD8/J97tkG3MDrEgEa1oMIXXf5cXoR1Nuz4Ie/o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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