SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b6ac9224cdca0f4d10e0d20bf447efbc043c7322de68593446a6242ae5810db9' 
  AND token = 'NUBIHLXVvHB42YjuBZVJX1gbXPUvHl0wYNSl/3m66Gg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}