SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5165964e8e23880d0fbb555a403dbee2dfd291b0937e0234cee3b41b45e8faa' 
  AND token = '6TSZ1WaRnbyq+KkasE6a+OM97HiflCKjTK8Wct9KaTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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