SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0338b38bfa85881873b921a7aae087c437fafff604fa5da2994f0fdef9e9c71' 
  AND token = 'oDMbPLDet9cmkOTeIm8IPnl6wgkImga3I4SMdHSs0dA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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