SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b33b6bed7b786e1f550bae99527e58462f5bc1fa1644c968c97e3dffd95f8131' 
  AND token = 'dL2pdxjiZiVaW9JlTHEz7Q2X++4hsLVV5cUknAwohHA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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