SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '629a0961811f2a44a73793052f97b449ea8c6ecdbcb37d380495fd6b4c7926c1' 
  AND token = 'K0sL/M3GFBVvfkexGuHpi+GUvYgMqVuiDqbvoJQLj5c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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