SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87c4d9cc7798140d7355be56444b0b7d828c08debe20255f6fe9d608ed416c09' 
  AND token = '8ck0BT5Y5Xtzopb5zzZfxjkzi91fvmze1krUx4QepNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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