SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6bc4363a369cc2a4e7b6e399e1914961ffec8d3a637088a29e8238ba27b7486' 
  AND token = 'uKdzLNMoLDLlCSLVyGltSp0vtVnF3gGZMQMsc1dHEiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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