SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b28f773e8dc02790ac44b91865adfab7a0b082e50c666fd451540147bb66a7fd' 
  AND token = '5+3t7ITOJJzMJ8yTGhEikOAjr4KmfOppyDHPSUGlWcw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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