SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f67e2b503ff38b2646ae3ea90a2f8bdd953b57a0b77447d3692c6d699656ebb8' 
  AND token = '6B34PRJNNDRrqFq1qamV1CCDLuULY8Bgkmu+totz4uI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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