SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a78d41306d00bc76fcdddd95d7c8598702d698256ee30a652a0d7184c236102' 
  AND token = '97zo9o+LoHL9/Jq+LfDiHWWnd0wUQUumSmCt2RmPLYk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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