SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca2dbc39fc32052492cd2cc46167605593e2e9a1e693b4818396c3b55672700b' 
  AND token = 'Nw/q2GgVU+Oo2szQ1/zFW04KUalgoLmlVCHDall6DTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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