SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4768954300efb0273adb969614fc5bdf24320c55e99d065128b0bdc6da082b45' 
  AND token = 'xPu4yWLuFCf/xYmsq/5tmGuiJvvmsgRL/U8KArZGgxs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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