SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a6861d3b669f3236668721db2c6805c512c12de3ba35a55097755ea6e8b1bbe' 
  AND token = 'ISlUx+Zc6MIL7ii0q6SQhjlj2KhtK81bFvOp+eg7pOE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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