SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b0b76cebc81d8dd39327100b5678739b59fa3642785f6f2b25c23f6609b42af9' 
  AND token = 'SnRobXofqVxcupM5EwZ/30Gc+U/vHS80VAdDfQG6wqk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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